this tells you that you that you do not have the required extension "GLX"

I did a 'Quick search" in (synaptic) package manager for "glx" and this is what I have listed/installed (running Nvidia graphics)in those specific search results:-

libgl1-mesa-glxlibgl1-mesa-drimesa-utils

If per chance you run Nvidia and you were to view your Nvidia X Server settings you would find under "Open GL/GLX Information", that Direct Rendering would be a negative or NO or not enabled or something similar

This doesn't reload metacity though, and I haven't found a smooth way to start it again short of a logout/login.I'm using an older ATI card (HD2600XT) with open drivers on two monitors, and somewhat of a noob myself so I'm not sure how to help.

I did some searching and found many folks using a script called compiz-check to troubleshoot. The authors blog entry with download instructions can be found here. My output from this script is as follows . . .

I learned a lot as I went (I think). Fglrx seems to like to have an /etc/X11/xorg.conf, and I approve of this. It's neat that the open source drivers are autodetected, but I never did find a good guide explaining how to tweak things on an install with no (and I guess no need for) an xorg.conf.

An important note, compiz is up and running happily on my system and the output of compiz-config is as follows . . .

At least one check had to be skipped: Error: No rendering method in use (AIGLX, Xgl or Nvidia)

If I did it again I'd try 'compiz --replace' as soon as the fglrx install was stable. I'd recommend trying without tinkering with xorg.conf as the above guide suggests first, as the hairiest moments came when I had to boot to recovery mode and comment out my alterations from the command line. I think I did a lot of extra fighting trying to make compiz-check happy when it wasn't necessary.

Everything I read suggests that the open source drivers are perfectly capable of running compiz, I just found a different way in my meanderings. I'm sure I've done it the hard way. I just thought to share what I could remember in case it helps someone later.

I learned a lot as I went (I think). Fglrx seems to like to have an /etc/X11/xorg.conf, and I approve of this. It's neat that the open source drivers are autodetected, but I never did find a good guide explaining how to tweak things on an install with no (and I guess no need for) an xorg.conf.

An important note, compiz is up and running happily on my system and the output of compiz-config is as follows . . .

At least one check had to be skipped: Error: No rendering method in use (AIGLX, Xgl or Nvidia)

If I did it again I'd try 'compiz --replace' as soon as the fglrx install was stable. I'd recommend trying without tinkering with xorg.conf as the above guide suggests first, as the hairiest moments came when I had to boot to recovery mode and comment out my alterations from the command line. I think I did a lot of extra fighting trying to make compiz-check happy when it wasn't necessary.

Everything I read suggests that the open source drivers are perfectly capable of running compiz, I just found a different way in my meanderings. I'm sure I've done it the hard way. I just thought to share what I could remember in case it helps someone later.